A conventional throttle control apparatus is disclosed in Japanese Patent Laid-Open Publication No. Hei 7(1995)-97950. This throttle control apparatus includes a DC motor that sets the position of the throttle valve in response to the corresponding accelerator pedal position. The DC motor is constructed in a way that includes numerous slots formed in the armature core. While such a DC motor can operate relatively quickly upon movement of the accelerator pedal position, the resultant positioning of the throttle valve is not achieved in a satisfactorily accurate manner due to the aforementioned construction of the DC motor.
Another type of known throttle control apparatus which is described in Japanese Patent Laid-Open Publication No. Hei 5(1993)-163988 employs a stepper motor instead of a DC motor. This apparatus, unlike the aforementioned apparatus, can achieve a positioning of the throttle valve with relatively great accuracy. However, the proper positioning of the throttle valve cannot be established in a relatively quick manner in response to the corresponding accelerator pedal position because the stepper motor is not able to rotate at a high speed.
In light of the foregoing, a need exists for a throttle control apparatus that can achieve a highly precise positioning of the throttle valve.
A need also exists for a throttle control apparatus which can establish a precise positioning of the throttle valve in a relatively quick manner.